The invention relates to a reel-hub for a tape, in particular a magnetic-tape or ink ribbon, which hub has cylindrical circumferential surface on which the tape can be wound and is divided into two semicylindrical reel-hub portions along a dividing zone. The reel-hub portions are interconnected integrally by means of an elastically deformable bridge which bound the dividing zone at one end, which bridge constitutes an articulation between the two reel-hub portions and whose circumferential bounding surface forms a part of the circumferential surface of the reel-hub. The reel-hub portions are held together by detachable connecting means arranged at the open other end of the dividing zone and which, to attach an end of the tape introduced into the dividing zone through the open end of said zone to the reel-hub, clamp said tape end between them along at least a part of the dividing zone.
Such a reel-hub, intended for a magnetic-tape, is known from U.S. Pat. No. 4,213,578. In this known reel-hub the two reel-hub portions are constituted by a main portion forming the major part of the reel-hub and a clamping portion which is integrally connected to the main portion by the limb and which forms only a small portion of the reel-hub. The clamping portion is separated from the main portion along a substantially tangential dividing zone and which is pivotable relative to the main portion substantially in the radial direction of the reel-hub between a position in which it is disengaged from the main portion and a clamping position in which it engages in the main portion.
As a result of the small size and the resulting short lever arm of the clamping portion this portion, when in its position in which it is disengaged from the main portion, must be pivoted through a comparatively large angle relative to its clamping position in order to ensure that the end of the magnetic-tape to be attached can be introduced into the dividing zone without being obstructed by the clamping portion. For clamping the magnetic-tape end to be attached the clamping portion must be moved through this comparatively large angle from its position in which it is disengaged from the main portion to its clamping position, which produces relatively large deformations of the elastically deformable bridge, which may give rise to a irregulatities in the circumferential surface of the reel-hub. Such irregulatities are very undesirable, because, if the reel-hub is not used for a long time, they manifest themselves as permanent deformations in the superimposed turns of magnetic-tape wound on the circumferential surface of the reel-hub. As the magnetic-tape is unwound from the reel-hub in an appropriate apparatus these deformations impair the uniform contact between the magnetic-tape and the magnetic head of the apparatus which cooperates with said tape for the purpose of recording and reproducing information signals on/from the magnetic-tape, resulting in the recording and reproduction quality of the information signals being degraded. Moreover, when the magnetic-tape is clamped on the know reel-hub the end of the magnetic-tape is clamped on the known reel-hub the end of the magnetic-tape to be attached can be introduced into the dividing zone between the reel-hub portions in a predetermined direction in only one position of the reel-hub but not in the inverted position of the reel-hub, because the open end of the dividing zone is oriented correctly relative to the end of the magnetic-tape to be attached only in said one position. When in the case of automated clamping the reel-hubs are fed in automatically, this is a disadvantage, because reel-hubs fed in the inverted position then have to be rejected. Moreover, since such a small clamping portion is less robust, the risk of damaging or breaking while handling said portion to clamp the magnetic-tape onto the reel-hub is comparatively high.